LCLS mirror switching of x-ray beam

The number of proposals for LCLS science has rapidly increased as all six LCLS x-ray instruments have come online. It created rising demand on beam time. Statistics shows that only about 25 % of LCLS proposals can be allocated beam time. One way to increase access is to share the x-ray beam between the different instruments. The purpose of this study is to quickly switch the x-ray beam between the Matter in Extreme Conditions (MEC) Instrument and the Coherent Xray Imaging (CXI) or X-ray Correlation Spectroscopy (XCS) Instruments, in order that two of the instruments can perform experiments simultaneously. In the most common operational mode, the MEC Instrument uses one x-ray pulse every 10 minutes, limited by the repetition rate of the high power nanosecond laser system. The MEC M3H mirror steers the x-ray beam to the MEC Instrument from the XCS or CXI Instruments. If the M3H mirror could switch the x-ray beam to MEC within a fraction of the 10 minutes waiting time, multiplexing of the x-ray beam would be achieved. The M3H mirror system has two motion stages for translation and rotation. The long path, 230 m, from the mirror to MEC hutch makes the pointing resolution 0f 100 microns and stability requirements challenging. The present study investigates such capabilities by measuring the correlation between the translation speed and the beam pointing reproducibility. We show that mirror translation can multiplex the LCLS x-ray beam.